Teaching Case

A 47-years-old woman referred to the breast unit of our institution to undergo her first mammography. There was no familial or personal history of breast cancer.
Clinical examination did not reveal breast asymmetry, nodules, nipple’s discharge or local pain. No axillary adenopathies were palpable.

The examination was performed using digital mammography (GE Senographe 2000D). Image acquisition included cranio-caudal (CC) and medio-lateral oblique (MLO) views. The CC and MLO views of the mammogram of the right breast show a dense breast with multiple scattered linear and round opacities (ranging from 1 mm to 4 mm in diameter) with high density, mainly located in the posterior third of the mammary gland. No other anomalies were observed in the rest of the breast. The CC and MLO views of the left breast do not show calcification, nodules, architectural distortions or significant axillary lymphnodes. An ultrasound (US) of the right breast showed multiple small masses with well-defined echogenic anterior surfaces and dirty shadowing in the right breast. Normal axillary lymphnodes were seen.

Cosmetic silicone injection in the body started in Japan in 1943, and afterward in the United States [1]. After the complications of this procedure became evident, it was banned [2]. Nevertheless, it continued to be used for its low costs in the undeveloped countries. Silicone was injected pure or with additives (like vegetable oil), trying to reduce its spread inside the breast, though this did not show a reduction in complications [3].
For breast augmentation, the silicone was directly injected into subdermal tissues or into the breast parenchyma, with or without image guidance [4].

Free liquid silicone breast injection (FLSBI) can be either asymptomatic or it may manifest with different local signs or symptoms like skin changes, mastodynia, adenopathies, mastitis, siliconoma and fibrosis [5]. Clinically, fibrous silicon-masses may be confusing and mimic carcinoma. Distant spread of siliconoma to other tissues and organs has also been reported [3,6].  

To our knowledge, we report the first case in the literature of FLSBI through the nipple for breast augmentation. The procedure was performed only in the right breast due to the pain arising after the procedure.  

On mammography, FLSBI into subdermal tissues or into the breast parenchyma appears as multiple round radiolucent masses, often with calcifications, or as large opacities, depending on the volume injected [7].
FLSBI through the nipple appears similar but with a different spatial arrangement. A network of multiple linear opacities may be observed spreading from the nipple into one or more regions of the breast, combined with small dense lobulated masses, which correspond to the lactiferous ducts and the terminal duct lobular units filled with silicone. These findings can also obscure breast carcinoma.  
On US, the most common finding for FLSBI is the “snowstorm sign” which consists of masses with a well-defined echogenic anterior margin and dirty shadowing. However, FLSBI may appear as hypoechoic or anechoic masses with or without posterior shadowing. US is the gold standard imaging technique to evaluate the silicone within lymphnodes, appearing as echogenic nodes with dirty shadowing [5].
Through MRI it is possible to define the linear collections or globular masses of FLSBI and to differentiate these from other fluids, owing to T1- and T2-weighted and silicone-selective sequences. Moreover, it is possible to differentiate between siliconoma and breast tumour using fat-suppression-T1-post-gadolinium sequences [3].

The treatment options include a watch-and-wait approach, while surgery is indicated in the presence of symptoms [5].
Our patient was reassured about the benign nature of the lesions and she was advised to perform an MRI with contrast-agent. The next mammogram was scheduled for the following year.

Take home message: FLSBI can obscure a breast cancer and then lead to a misinterpretation of the screening mammographies; imaging findings should be always correlated to the clinical history of the patient.

Written informed patient consent for publication has been obtained.